This invention relates to dermatomes, useful for surgical operations such as skin grafting and tangential excision, particularly to dermatome wherein the cutting blade may also be actuated for a reciprocal motion by mechanical means, usually comprising electrical motor means.
Dermatomes, used for surgical operations and particularly for skin-grafting purposes, are known in the art. They comprise a cutting blade, which reciprocates in a direction essentially perpendicular to the direction of advancement of the dermatome, and handle means or the like for controlling and displacing the dermatome as required. The blade may be actuated in its reciprocating motion, either manually or by mechanical means, which are usually electrical or gas turbine motor means. A suitable electrical power or gas supply source is provided, and usually is a central source connected to said motor means by cables or tubes, as the case may be.
U.S. Pat. No. 2,579,029 describes a dermatome with a manually reciprocated knife coupled with suction means for drawing the skin to be cut closely against the cutting blade, the length of the cut being limited by the width of the suction means and the blade. The dermatome is provided with a handle by which the dermatome is maneuvered and advanced in the desired direction of the surface on which the skin may be cut, which handle is also used for actuating the knife in its reciprocating motion.
U.S. Pat. No. 3,428,045 is intended to be an improvement on the aforesaid U.S. Pat. No. 2,457,772. It is constituted by a frame, comprising a pair of opposite side members connected by a foot plate riding on the skin, a pressure plate mounted between the side members forwardly on the footplate, an oscillatory cutting element having its cutting edge forwardly off the foot plate and rearwardly off the pressure plate, for adjusting the pressure plate vertically for determining the depth of the cut, and assuring exact parallelism of the pressure plate with the forward edge of the foot plate. The dermatome further comprises means for actuating the blade in its oscillating movement. They are not described, and are stated to be any suitable means which form no part of the invention of the said patent. The width of the skin section to be taken is controlled by means of adjustable guide plates, one on either side of the dermatome, which underlie the blade and the foot plate and are slidably mounted on supporting rods. The dermatome is maneuvered by means of a handle which is fitted on an axial plane of the instrument, the plane being parallel to the motion of the dermatome and perpendicular to the blade edge.
DAS 2916268 describes a dermatome, characterized by the presence of swingable guide plates transversely juxtaposed of the cutting blade, which can be raised to expose the skin to the cutting blade or lowered to prevent contact of the skin with said blade. This patent does not describe a handle nor means for actuating the cutting blade. However, it does not have the features described in this application nor in the art, manufactured by Aesculap-Werke RG, the applicant of the aforesaid application, DAS 2916268, and they have a motor actuated cutting blade and a handle situated in an axial plane perpendicular to the cutting blade. The cut is limited in this dermatome, as well as in the dermatome described in the aforesaid DAS, by cutting elements located laterally of the cutting blade edges.
U.S. Pat. No. 4,690,139 is a hand-actuated dermatome with a guard for controlling the cutting depth and an adjusting mechanism for effecting an angular displacement between the guard and the cutting depth, the guard extending the complete length of the cutting edge of the blade and being rounded at its opposite end, enabling the full blade length to be used. The dermatome includes a handle which is offset from the plane on the head of which the cutting blade is mounted, and is pivoted from the first position overlying said head to a second position extending laterally of, but offset from, said head.
All the powered dermatomes known in the art have blades that are rather short (e.g., 10 cm of less), and thus the width of the incision and the resulting width of the graft is limited to narrow strips. The manual dermatomes have longer blades (more than 14-15 cm) with a resulting, potential, wide cutting front and wide graft. The dermatomes in which the blade is manually actuated are problematic. They require a considerable physical effort and technical skill on the part of the operator to produce a desired cutting, permit to use the central length of the blade in the cutting operation, except for the dermatome described in U.S. Pat. No. 4,690,139, in which the entire length and even the corners can be used. On the other hand, the dermatomes in which the blade is mechanically actuated may be much more efficient in their cutting operation but are so constructed that they can be advanced by pushing forward over the treated area of the skin substantially only in a direction perpendicular to the cutting blade, which makes it very difficult to operate over small skin areas or areas having a complex shape and renders the treated skin areas not as fully visible to the operator as they should be. Another drawback, common to all the dermatomes (except that of U.S. Pat. No. 4,690,139) is the geometry of the blades"" ends, which are complex, have sharp angles, protrusions or ridges, and do not allow sidewise movement when the blade touches the skin.
Furthermore, said mechanically actuated dermatomes have sterility problems which exist practically in all surgical instruments which comprise an actuating electrical motor, and other electrical components, of non-stainless metals and other non-metallic materials. Absolute sterility of all the surgical instruments is required and any danger of pollution, no matter how minimal, must be avoided. For this purpose, the instrument is sterilized and is used in a completely sterile environment. However, the electrical motor, as well as the batteries, if it is battery-operated, cannot be subjected to the standard, xe2x80x9cflashxe2x80x9d autoclaving, sterilizing operation, which requires high temperatures and vapor pressures. For this reason most dermatomes are connected to a main electrical or gaz source by a flexible line. These lines cannot be autoclaved and should be gaz-sterilized, a method that demands time (24-48 hours) and means. It is possible, of course, to introduce the motor, and the batteries, if any, into the housing of the surgical instrument, which housing can be closed hermetically. However, contact between the non-sterilized motor and batteries can occur while it is introduced into the housing. Transitory contact of this kind is sufficient to destroy the absolute sterility that is required of the instrument and of the environment. In order to prevent this problem from arising, in one instrument (sold under the trade name Aesculap(trademark)) a separate plastic tunnel is provided to ensure a safe and non-contaminating passage of the non-sterile motor and batteries into the sterile housing. This tunnel has to be kept for use and discarded afterwards.
It is therefore a purpose of this invention to provide a mechanically-actuated dermatome which can be used over skin areas that are small or of complex shape.
It is another purpose of this invention to provide such a dermatome which allows the operator full visibility of the treated skin areas and access thereto.
It is a further purpose of this invention to provide such a dermatome which can be maneuvered by the operator most easily straight forward and sidewise, and with a minimum effort, on any skin surface.
It is a still further purpose of this invention to provide such a dermatome that can incise and excise tangentially very thin or thicker layers of skin or other tissues.
It is a still further purpose of this invention to provide a mechanically actuated dermatome that can be used as a hand actuated dermatome, in case of power failure.
It is a still further purpose of this invention to provide a surgical instrument, particularly but non exclusively a dermatome, comprising an electrical motor and/or batteries, which can be inserted into a housing, after the sterilization of the instrument, without in any way taking the risk of contamination of the sterilized instrument and therefore the sterile surgical environment and field.
It is a still further purpose of this invention to provide a surgical instrument that may be powered manually or by an electrical power pack that can be used and served by a single operator. For this requirement the operator, scrubbed, gowned and gloved, should be able to load, remove and reload the non-sterile, contaminated power pack into the sterile dermatome without breaking the operation room aseptic rules.
It is a still further purpose of this invention to provide a mechanically actuated dermatome that can excise as wide a front as in manually actuated dermatomes.
It is a still further purpose of this invention to provide an improved cutting instrument which can be maneuvered by the operator most easily and with a minimum effort.
Other purposes and advantages of the invention will appear as the description proceeds.
The dermatome according to the invention is a mechanically actuated dermatome, comprising a handle, to be gripped by the operator in order to control it, which handle is substantially perpendicular to the plane of the cutting blade. Said blade is a flat body and its upper and lower surface lie in parallel planes, and each of said planes, or any other plane parallel to them, can be considered as the cutting blade plane, for the purposes of defining the orientation of the handle.
Preferably, the blade and the mechanism actuating it in alternating motion are enclosed in a housing which has a lowermost surface that rides on the skin during treatment. Said lower surface is essentially parallel to the plane of the blade and the handle is substantially perpendicular to it and, of course, directly upwards when the dermatome rests on said lowermost surface of said housing.
The aforesaid, substantially perpendicular, orientation of the handle can be exactly determined if the handle is cylindrical or at least has circular cross-section, in which case the handle has a geometric axis and its orientation is that of said axis. If the handle does not have a geometric axis, then the general orientation that a hand assumes when it grips it to control the dermatome, will be considered as the orientation of the handle. Portions of the handle which the operator""s hand does not contact when it controls the dermatome, will not be considered in determining the axis of the handle and in general its orientation. In general, only the part of the dermatome that is gripped by the operator when controlling the dermatome, is considered herein as being xe2x80x9cthe handlexe2x80x9d, and this term should be so construed in this specification and claims.
A perpendicular orientation of the handle permits the best control of the dermatome with the minimum effort.
Preferably, said blade housing and all other parts of the dermatome are so configured as to expose the ends of the blade, so that the dermatome may be slanted (if needed) by the operator to work on the skin only along a terminal portion thereof, adjacent to one of its ends.
According to another preferred embodiment of the invention, the blade housing is constructed in such a way that its entire underside (the one that comes in contact with the skin) is smooth, without any protrusions, sharp corners or any other obstacles to the reciprocated movement along its long axis against the skin. This feature is mandatory to allow the use of said dermatome as a manual dermatome.
According to another preferred embodiment of the invention, the two blades corners that are at the proximal and distal ends of the blades cutting front are hidden and protected from the skin by rounded protrusions, that are part of the base plate of the blade housing. In this embodiment, these two blades ends protectors differ what is disclosed in U.S. Pat. No. 4,690,139, of the present applicant, as in this latter the blade is stationary with respect to the housing and blades ends protectors, while in the dermatome of the present invention the blades slides in its reciprocal or continuous movement against and above these protectors and are different in size and design.
According to another preferred embodiment of the invention, the adjustable blade guard that determines the thickness of the excised tissue has rounded ends that surround the proximal and distal ends of the housing, thus facilitating the reciprocating or continuous movement of the entire housing and of the dermatome against the skin when used in its manual mode and its control in different than straight forward direction when used in its mechanically powered mode.
According to another, preferred feature of the invention, the dermatome handle, or the part of the dermatome that comprises the handle, as hereinbefore defined, is hollow and constitutes a housing for the motor, with or without batteries, which, in either case, constitutes what will be called xe2x80x9cthe power packxe2x80x9d. Said housing is provided with a cover, removable to permit insertion of the power pack, but adapted to be applied to the handle to provide air-tight closure and to prevent contact of the non-sterile power pack with the environment and possible, consequent contamination. The batteries, when the motor is fed by batteries, may be housed in the same hollow handle or part comprising the handle, or in a separate battery housing connected to, but separate from, said handle, said separate housing being similarly provided with a removable cover, adapted to be applied to it to prevent contact of the batteries with the environment. A common cover may be provided, in this case, for both the motor and the battery housing. Said cover is provided with means for engaging the non-sterile power pack and means for engaging and close-locking into the housing. Both engaging-locking means can be operated remotely from the sterile surfaces by the scrubbed-sterile operator.
According to a more preferred feature of the invention, means are provided for preventing contact of the motor and the batteriesxe2x80x94viz. the power packxe2x80x94with the respective housings or with the common housing, when they are introduced into said housing or housings. Said means preferably comprise circumferential, hollow diaphragm or barrier means that are internally engaged by the motor and the batteries, if any, when the same are introduced into the housing or housings, and externally engage the inside of said housing or housings, thereby preventing contact of the former with the latter, said diaphragm means being introduced into said housing or housings, together with the motor and the batteries, and being isolated from the environment once the cover or covers are applied to the housing or housings. The shape of said diaphragm means is determined by the shape of the housing or housings with which they cooperate and with which they are structurally connected and/or of which they are a part. They are preferably sleeve-like bodies, made of thin metal plate, stainless or protected against rust and other surface contamination. Convenient metals are stainless steel, aluminum, titanium, etc. Said sleeve-like body can be replaced by a retractable guide (rod or rail) that extends above the housing level, is designed to engage the power-pack and guide its descent into the housing without touching any part of said housing.
It will be understood that said means for preventing motors and/or batteries, or any non-sterilizable parts that are required to be introduced into housings that are part of a surgical instrument, in order to operate the instrument, from contacting said housings, when they are introduced into them, can be used in any surgical instrument, besides a dermatome, to prevent contamination and assure complete sterility, and in such a case should be structured and shaped so as to be adapted to the surgical instrument. Therefore this invention comprises said contamination preventing means for application to any surgical instrument, a corresponding method for preventing contamination of surgical instruments, and any surgical instrument comprising said contamination preventing means.
Therefore the invention also comprises a device for preventing the contamination of sterilized surgical instruments into which non-sterilizable parts are to be introduced into housings of said instruments to operate them, which comprises diaphragm or barrier or a guiding mean engaged by the non-sterilizable parts, when the same are introduced into the housings, said diaphragm means being introduced into said housings, together with said non-sterilizable parts, and being isolated from the environment once covers are applied to said housings.
The invention further comprises a method for preventing the contamination of sterilized surgical instruments into which non-sterilizable parts are to be introduced into housings of said instruments to operate them, which comprises interposing diaphragm or barrier means between the non-sterilizable parts and the sterilized housings, when the said non-sterilizable parts are being introduced into said housings, and introducing said diaphragm means into said housings together with said non-sterilizable parts, and sealing said housings from the environment.
The invention further comprises sterile means for holding, removing or introducing the power pack into said diaphragm or the guide and the sterile housing. Said means may be part of the lid-cover that is designed to close hermetically the power pack housing. The actuating switch of the motor is situated on an accessible part of the handle and allows to turn on and off the motor without violation of the instrument external asepsis.
The invention further comprises means for an accurate tangential excision of thin or thicker layers of skin. These means are an exceptionally long amplitude (e.g.  greater than 6 mm) and a high (e.g. RPM greater than 3500/min) of reciprocal movement of the blade compared to its housing when the power pack is used, or a continuous movement of a round, strip-like blade.
The invention also comprises a mechanically actuated cutting instrument intended for use in contact with the human skin, in particular a shaving instrument, having a cutting blade mechanically actuated in a reciprocating moton and power means for actuating it, and further comprising a handle, to be gripped by the operator in order to control it and to displace it over the surface to be treated, which handle is substantially perpendicular to the plane of the cutting blade, as defined with reference to dermatomes. Such a cutting instrument has essentially the same structure as the dermatome hereinbefore defined and described in detail hereinafter, and the features described with respect to the dermatomes apply to it as well, except that it will generally built on a smaller scale, adapted to its use, and generally may not be required to be completely sterile. Obviously, it will be used in an appropriate manner, viz. it will be caused to slide over the skin without applying such pressure as would cause it to cut into it.